The several objectives of this research include studies of the cell-free biosynthesis of the antibiotics, tetracycline, penicillin and cephalosporin and the 13C-labeled study of the biosynthesis of the anti-tumor antibiotic hedamycin. A new theory for pencillin and cephalosporin biosynthesis will be tested via cell-free studies. This work will lead to a deepening of our understanding of the biosynthetic pathway for many classes of natural product structures.